Automated equipment for washing automobiles has been made in two general types. Firstly, are the tunnel car washers, wherein the washing equipment is essentially stationary and the automobile is drawn through the equipment by a conveyor built into the floor. Such a tunnel car wash has numerous nozzles spraying water and cleaner onto the car passing through, side brushes for cleaning the sides of the automobile and wheels, top brushes or stripped curtains cleaning the hood and top of the automobile passing through, rinse water nozzles and air jets for drying the automobile.
The other type of car wash assumes that an automobile is driven into a certain location and then parked. The automatic washing equipment, sometimes known as a roll over car washer, then moves on tracks on the floor, and along and over the automobile. In the past, such equipment has used rotary side brushes for washing the sides of the car, and movable on long arms for traversing the ends of the automobile as well. Rotary brushes move over the hood, and top and trunk lid of the automobile, and move up and down as the car washer passes along the automobile. The top brush and the side brushes have been of plastic bristle type material, which scrub as they revolve against the surfaces of the automobile. Such plastic bristles are stiff, smooth surfaced strands with a length often in the range of 12 to 18 inches. These brushes are sufficiently stiff as to be self-supporting while protruding substantially radially from the mounting axle without significant flexing. These types of roll over car washers using plastic bristle brushes are rather hard on the finish or paint of the automobile body because of the stiffness of the bristles and also because often these car washers are used without any soap in the water, and this produces some scratching of the paint or surface finish. In addition, even though soap is used, the plastic bristles rapidly shed the liquid because the bristles whirl around at a high rate of speed and throw off any liquid that may temporarily be sprayed onto such bristles.